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J. H. BUNNELL.

I TELEGRAPH SOUNDER. No. 267,833. Patented Nov. 21, 1882.

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W By hi; .Attorneys N PETERS, Phnto-Lilhcgnphnr. wmin m. n. c.

. UNITED STATES PATENT OFFICE.

JESSE H. BUNNELL, OF NEW YORK, N. Y.

TELEGRAPH-SOUNDER.

SPECIFICATION forming part of Letters Patent N 0. 267,833, dated November 21, 1882.

Application filed October 19, 1882.

graphic service, by means of which the operator interprets the communication transmitted from adistantstation by listeningto the sounds produced by the to-and-fro vibration of the armature-lever of an electro-magnet between two fixed points or stops. V

Hitherto it has been usual to attach the electro-magnetic apparatus and stops rigidly to a board, preferably of hard wood possessing resonant qualities, and to secure such base firmly to the upper surface of, a table or shelf, either directly or by means of a stifi metallic base or frame surrounding the base-board of the instrument and rigidly secured thereto, and also to the-table. In an apparatus thus mounted the blows of the armature-lever are received upon a metallic sounding-post, and the vibrations of the post are communicated to the base and thence to the table to which it is secured. Thus the table forms, in some sort, a resonator, for re-enforcing and strengthening the soundvibrations imparted to it by the sounding-post. This construction of the apparatus, however, presents certain objectionable features. The sounds produced are almost entirely dependent upon the character of the table or shelf upon which the apparatus is placed, and in case it is necessary to place the instrument upona solidsurface incapable of being thrown into vibration the sounds produced are not only weak in volume but of a harsh and disagreeable tone. In case the metallic base orframe is employed, it has been usual to clamp the base-board of the instrument thereto by each of its four edges,

thereby checking its sonorous vibration, and.

materially injuring the volume and quality of tone of the instrument. An additional and very serious objection often arises from the circumstance that the vibrations communicated to the supportingtable by the apparatus in the manner hereinbefore described are necessarily imparted to other independent instruments (No model.)

standing upon the same table, and in the case of delicately-adj usted relays and other like receiving-instruments their normal operation is thereby interfered with.

The object of my invention is to provide a reason ator or sounding-board for a telegraphic receiving apparatns of this character, which shall beattached thereto and supported in such a manner as to freely take up the sonorous vibrations produced by the impact of the armature-leverand tore-enforceand strengthen them to the required degree without imparting them to the table or other support upon which the entire apparatus rests.

In the accompanying drawings,Figure l is a vertical longitudinal section of an apparatus embodying myiuveution, and Fig. 2 is an inverted plan of the same.

The operative parts of the sounder which I have represented do not differ from those in ordinary use. They comprise an electromagnet, M, having a soft-iron armature, m, rigidly secured to a horizontal metallic lever, L, which is pivoted at lto a stationary metallic support, N. When the armature m is attracted by the electro-magnet M the lever L impinges upon a sounding-post,- P, which is preferably constructed in the form of a bridge or arch, as shown in the figure. the lever, when released by the demagnetization of the electro-magnet M, is caused by the retractile force of an adjustable spring, S, and is limited by an adjustable stop, El, mounted upon the bracket 1), projecting from the sounding post or arch P. The downward. excursion of the lever may be adjusted by means of a suitable stop, I. The sounding-post P is firmly secured at its foot to a resonator or soundingboard, B, by means of suitable screws, 6 e, or other equivalent means. The electro-magnet M is in like manner preferably secured to the sounding-board by means of screws ff. The resonator or sounding-board B (which I pre fer to construct in the form of an oblong parallelogram with round corners, as shown in the figure,) maybe made of any suitable resonant material, such as hard wood, metal, or

The upward motion of glass, theformer being generally preferable.

The sounding-board B is mounted within and surrounded by a rigid metallic frame, A, which is designed to be rigidly secured to a table or a ceases other convenient support by means of screws passing through suitable apertures, a a. Although the metallic frame A entirely surrounds the sounding-board B, the two are separated from actual contact with each other, except as hereinafter stated, by a narrow space, as shown at b. The sounding-board is rigidly clamped or secured to the frame A at one of its edges only, leaving its remaining portion free to vibrate in a manner hereinafter to be described. This is effected by means of three projecting supports, 0 G 0, upon the inner surface of the frame A, to which supports the sounding-board is rigidly secured by means of screws 0 0 0. Thus it will be understood that while the oblong sounding-board B is rigidly clamped or fastened to the base A by one of its shorter edges its remaining-portions are left free to take up and re-enforce the vibrations set up by the impingement of the lever L upon the sounding-post P. The vibrations are, however, confined to the sounding-board, and are not transmitted through the rigid metallic frame A to the table beneath.

By means of the hereinbefore described organization of parts I am enabled to obtain a as a stop and support for the latter in such case.

I claim as my invention- 1. The combination, substantially as hereinbefore set forth, of an electro-magnet, amovable arm ature-lever, a stationary sounding post or bridge upon which said lever impinges, a

resonator or sounding-board to which said sounding post or bridge is rigidly secured, and a stationary base or support to which said resonator or sounding-board is clamped by one of its edges only, thereby leaving-its remaining portion free to take up the vibrations of the sounding-post.

2. The combination, substantially as hereinbefore set forth, of an electro-magnet, a movable armature-lever, a stationary sounding post or bridge upon which said lever impinges. a resonator or sounding-board to which said sounding-post and electro-magnet are respectively secured, and a stationary base or support to which said resonator or sounding-board is clamped by one of its edges only.

3. The combination, substantially as hereinbefore set forth, of a rigid base or frame surrounding a resonator or sounding-board and clamped thereto by one of its edges only, and a telegraphic sounder mounted upon that portion of said sounding-board which is free to vibrate.

In testimony whereof I have hereunto subscribed my name this 10th day of October, A. D. 1882.

' JESSE H. BUNNELL.

Witnesses: I

DANIEL W. EDGECOMB, MILLER G. EARL. 

